In analysis and evaluation of the performance of a surface irrigation system, basin surface roughness is generally adopted to represent the impact of surface resistance on surface water flow movement. Under mechanized farming and sowing conditions, the crop layout structure formed by farming and cultivation and partial unevenness of the land surface usually present specific directivity, and thus the resistance against the surface water flow passing through any spatial position of a basin has anisotropic characteristic; therefore, an anisotropic basin surface roughness model having apparent two-dimensional characteristics is required for quantitative description, to improve the simulation precision of surface water flow movement in surface irrigation, thereby improving the evaluation capability on the performance of the surface irrigation system.
The current measurement approach of anisotropic basin surface roughness is limited to a circumstance that shallow furrows on a basin surface and crops are parallel or perpendicular to ridges of basin; however, when the shallow furrows on the basin surface and the crop planting direction form a certain rotation angle with the ridges of basin, isotropic basin surface roughness having only one-dimensional characteristics is commonly measured, and is used to replace the anisotropic basin surface roughness having two-dimensional characteristics, which greatly reduces the simulation precision of a surface irrigation hydrodynamics process and further reduces the evaluation accuracy of the performance of the irrigation system.
In view of the above, in the case that the shallow furrows on the basin surface and the crop planting direction form a certain rotation angle with the ridge of basin, a method for measuring anisotropic basin surface roughness needs to be provided, and based on a mathematical tensor property of anisotropic basin surface roughness, the present invention provides a method for acquiring anisotropic basin surface roughness and use thereof, which are simple, practical, accurate and reliable.